S125-E-007224 (14 May 2009) --- Astronaut John Grunsfeld performs work on the Hubble Space Telescope as the first of five STS-125 spacewalks kicks off a week's worth of work on the orbiting observatory. Grunsfeld, a spacewalk veteran with a long relationship with the telescope, will participate in two of the remaining four sessions of extravehicular activity later in the mission.